Radiation-induced taste aversion in laboratory animals may serve as a model for taste aversions and subsequent anorexia observed in clinical radiation therapy patients. Since the typical radiation procedure used in animal studies differs in a number of important aspects from the exposure conditions employed in clinical situations, it is proposed to study the establishment of radiation induced taste aversion in rats under treatment conditions which mimic clinical procedures. This will involve taste aversion studies with multiple, low-dose, partial-body radiation exposures instead of the usual single, high-dose, whole-body irradiation procedures employed in animal studies. Once the effects of these treatment parameters are established, techniques for blocking radiation-induced taste aversions in rats will be investigated. Specifically, the effects of different doses of antihistamines as well as food deprivation before and after irradiation will be studied to determine the optimal treatment regimen for blocking taste aversions. It is hoped that these studies will suggest prophylactic measures which can be used in clinical radiation therapy. Since treatments such as antihistamine injections could compromise the clinical effectiveness of the radiation in destroying cancer cells, studies will be conducted to test for these effects. In addition, extensive but not invasive data collection will be initiated with human radiation therapy patients. Based on information obtained from hospital records, questionnaires, daily interviews and diaries we will evaluate the incidence of dietary problems, in particular changes in dietary habits, experienced by radiation therapy patients. The initial goal will be to determine whether some of the dietary problems encountered in clinical radiation therapy are the result of radiation-induced taste aversion.